Tag Archives: medicine

Paging Mustapha Mond

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Increasingly, Couples Use Embryo Screening  

"More and more couples are turning to an embryo-screening technique that allows them to choose the genetic makeup of their children, according to a survey released yesterday in the online edition of the journal Fertility and Sterility."

"Son, we love you, especially since you turned out just like the clinic promised you would."

Oh brave new world, that hath such people in't…*shudder* 

Plan B: Literature Review (Part I)

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The mode of action of [emergency contraception, EC] has become he subject of heated debate in North America and in several Latin American and Caribbean countries. The main question is centred on whether or not EC prevents pregnancy by interfering with post-fertilization events. This issue is of importance for many people who consider that a new human life begins at the time that fertilization is completed. Accordingly, interference with post-fertilization events would lead to loss of human life. In spite of a lack of scientific evidence to support a post-fertilization effect, this possibility is used as an argument to turn legal, political and religious constituencies against the availability and use of EC. (Ortiz, et al, 2004)

In order to satisfy my own curiosity and my critics, I’ve reviewed recent scientific literature related to the question of whether or or not Plan B is abortifacient. I do not wish to appear to be in any way “rooting” for Plan B and/or its supporters. I am not. However, I have been very frustrated by the way that many of my fellow pro-lifers have repeatedly stated confidently that Plan B sometimes acts after fertilization and is therefore abortifacient. I do not believe such confidence is supported by scientific evidence. The goal of this literature review is to present a fair appraisal of the likelihood of postfertilization effects caused by Plan B to the pro-life community.

For the most part my analysis will proceed in chronological order, but I’ll begin with a newer article (Croxatto, Ortiz, and Müller, 2001) that provides an brief primer on the relevant reproduction science. Continue reading →

Plan B: Preview of Literature Review

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In order to satisfay my own curiousity and my critics , I've begun a review scientific literature related to the question of whether or or not Plan B is abortifacient . Here are the articles currently on my reading list. Feel free to suggest others.

  1. Croxatto HB, Devoto L, Durand M, Ezcurra E, Larrea F, Nagle C, Ortiz ME, Vantman D, Vega M, von Hertzen H. Mechanism of action of hormonal preparations used for emergency contraception: a review of the literature. Contraception 2001;63(3):111-121.
  2. Durand M, del Carmen Cravioto M, Raymond EG, Duran-Sanchez O, De la Luz Cruz-Hinojosa M, Castell-Rodriguez A, Schiavon R, Larrea F. On the mechanisms of action of short-term levonorgestrel administration in emergency contraception. Contraception 2001;64(4):227-234.
  3. Kahlenborn C, Stanford JB, Larimore WL. Postfertilization effect of hormonal emergency contraception. Ann Pharmacother 2002;36(3):465-470.
  4. Croxatto HB, Ortiz ME, Muller AL. Mechanisms of action of emergency contraception. Steroids 2003;68(10-13):1095-1098.
  5. Muller AL, Llados CM, Croxatto HB. Postcoital treatment with levonorgestrel does not disrupt postfertilization events in the rat. Contraception 2003;67(5):415-419.
  6. Croxatto HB, Brache V, Pavez M, Cochon L, Forcelledo ML, Alvarez F, Massai R, Faundes A, Salvatierra AM. Pituitary-ovarian function following the standard levonorgestrel emergency contraceptive dose or a single 0.75-mg dose given on the days preceding ovulation. Contraception 2004;70(6):442-450.
  7. Gemzell-Danielsson K, Marions L. Mechanisms of action of mifepristone and levonorgestrel when used for emergency contraception. Hum Reprod Update 2004;10(4):341-348.
  8. Ortiz ME, Ortiz RE, Fuentes MA, Parraguez VH, Croxatto HB. Post-coital administration of levonorgestrel does not interfere with post-fertilization events in the new-world monkey Cebus apella. Hum Reprod 2004;19(6):1352-1356.
  9. McGregor JA, Equiles O. Risks of mifepristone abortion in context. Contraception 2005;72(5):393-393.
  10. Mikolajczyk RT, Stanford JB. A new method for estimating the effectiveness of emergency contraception that accounts for variation in timing of ovulation and previous cycle length. Fertility and Sterility 2005;83(6):1764-1770.
  11. Pruitt SL, Mullen PD. Response to letters to the editor regarding Contraception or Abortion? Inaccurate Descriptions of Emergency Contraception in Newspaper Articles, 1992-2002. Contraception 2005;72(5):396-397.
  12. Pruitt SL, Mullen PD. Contraception or abortion? Inaccurate descriptions of emergency contraception in newspaper articles, 1992-2002. Contraception 2005;71(1):14-21.
  13. Spinnato II JA, Mikolajczyk R. Emergency contraception — a different interpretation. Contraception 2005;72(5):395-395.
  14. Stanford JB, Larimore WL. Description of Emergency Contraception in the Media. Contraception 2005;72(5):394-395.
  15. Trussell J, Jordan B. Mechanism of action of emergency contraceptive pills. Contraception 2006;74(2):87-89.

A Spectral Smack-Down

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Arlen Specter reamed out Advanced Cell Technologies scientist Rober Lanza for their hype about having found a way to non-lethally harvest embryonic stem cells. As you may have heard, this development was only theoretical, as all of the embryos were destroyed so all their cells could be harvested and the chances of getting viable embryonic stem cells would be optimized. And since the success rate was two percent, "optimized" is very relative. We therefore cannot say that we have a non-lethal (let alone non-harmful) method of harvesting human embryonic stem cells (hESCs).

At first, ACT was only guilty of hype, which it has done before, but now folks on the web are calling out Lanza for having left out some critical details: when the AJOB blog, which is very pro-embryonic research, has an entry called "Paging Dr. Hwang?", you know something juicy came out.

What folks now say is that ACT soaked the harvested cells (blastomeres, to be precise) in the same dish as the original embryo, providing some cellular signals that would help the harvested cells live and be viable embryonic stem cells. This doesn't nullify the ultimate premise of their research, but it's black eye for Nature and a further disgrace to ACT. Perhaps ACT wanted this technique for themselves, and while they wanted the hype of a Nature article, they didn't want competitors replicating those results.

 (HT: Wesley Smith, who has posted half a dozen entries on this topic. You'd be well-served to read his and AJOB Blog's many fine points about this issue, particularly AJOB's entry on the "Kevorkianization of Stem Cell Research"–I'll even forgiven them for conflating all stem cell research with embryonic stem cell research…this time. 😉 )